The present invention relates to a toner cartridge and a mechanism for detecting remaining quantity of toner.
FIG. 25 illustrates a conventional toner chamber and a toner agitator provided therein.
FIG. 26 illustrates a toner chamber of a conventional toner cartridge when the toner chamber is nearly empty of toner.
FIG. 27 illustrates the toner chamber of the conventional toner chamber when the toner chamber holds a sufficient amount of toner.
FIG. 28 illustrates the output signal of a toner sensor indicative of the remaining toner in the toner chamber.
Referring to FIG. 25, a toner agitator 92 is free to rotate in a toner chamber 91. The toner chamber 91 has a gear, not shown, rotatably attached thereto. The gear 95 has a projection 94 that pushes the toner agitator 92 when the gear 95 rotates. As the gear 95 rotates in a direction shown by an arrow, the projection 94 pushes the toner agitator 92 so that the toner agitator 92 rotates together with the gear 95. When the toner agitator 92 rotates past its highest position in the toner chamber 91, the toner agitator 92 drops due to its own weight. If the toner chamber 91 holds a sufficient amount of toner therein as shown in FIG. 27, the toner agitator 92 leaves the projection 94 to land and rest on a pile of toner. If the toner chamber 91 holds little toner therein as shown in FIG. 26, when the toner agitator 92 rotates past its highest position, the toner agitator 92 drops and rotates to its lowest position due to its own weight. After the toner agitator 92 drops from its highest position, the gear 95 still continues to rotate so that the projection 94 pushes the toner agitator 92 again to rotate together with the toner agitator 92. The toner agitator 92 stays at its lowest position for a longer time period when the toner chamber 91 holds little toner therein than when the toner chamber 91 holds a sufficient amount of toner therein.
A magnet-sensitive toner sensor, not shown, is disposed outside of the toner chamber 91. The toner agitator 92 has a magnet attached thereto. As the toner agitator 92 rotates, the magnet passes the toner sensor. The toner sensor detects the magnetic flux of the magnet and outputs a sensor output as shown in FIG. 28.
Referring to FIG. 26, when the toner agitator 92 is within an angular range xcex1, the toner agitator 92 is substantially at its lowest position and the toner sensor outputs a signal indicative of xe2x80x9ca toner-low.xe2x80x9d
The conventional toner agitator 92 suffers from a problem that the toner agitator 92 tends to oscillate back and forth about its lowest position when the toner chamber 91 holds little toner therein.
An object of the invention is to solve the drawbacks of the aforementioned conventional art. A toner cartridge includes a toner holding section, a toner agitator, a damper, and a position indicator. The toner holding section is a toner chamber that holds toner therein. The toner agitator is disposed in the toner holding section and is free to rotate. The toner agitator is driven in rotation to agitate the toner when it is pushed to rotate. The damper damps the motion of the toner agitator when the toner agitator rotates freely, the damper being disposed in the toner holding section. The position indicator is attached to the toner agitator and indicates the rotational position of the toner agitator.
The damper is disposed in a path through which the toner agitator rotates, the damper defining an angular range through which the toner agitator rotates while the position indicator is detected by an external device.
The damper is formed of a resilient film material and is bent into a base portion, and a raised portion. The base portion is fixed to an inner surface of the toner holding section and the raised portion extends into the path.
The raised portion exhibits a first resistance against a first force that causes the raised portion, to deform inwardly relative to the angular range and a second resistance against a second force that causes the raised portion to deform outwardly relative to the angular range.
The damper is one of two dampers. A first one of the two dampers is disposed at an upstream end of the angular range with respect to rotation of the toner agitator. A second one of the two dampers is disposed at a downstream end of the angular range with respect to rotation of the toner agitator. The raised portion of the second one of the two dampers lies in a plane at an angle with a plane in which the raised portion of the first one of the two dampers lies.
The toner agitator stays in the angular range for a shorter time when the toner cartridge holds a larger amount of toner therein than when the toner cartridge is nearly empty of toner.
The raised portion has a plurality of slits extending in a direction in which the raised portion extends.
The toner agitator is pushed by a drive member to rotate about a substantially horizontal axis. When the toner agitator is rotated past its vertical highest position, the toner agitator drops from the vertical highest position due to its own weight. When the toner agitator is in the angular range, the external device detects the magnetic field.
The position indicator is a magnet attached to the toner agitator. The magnet radiates a magnetic field that is detected by the external device.
A toner remaining detector for detecting a remaining amount of toner in a toner cartridge attached to an image-forming unit, the detector includes a toner agitator, a position indicator, and a damper. The toner agitator is disposed in the toner cartridge and is free to rotate about an axis. The toner agitator is driven in rotation to agitate the toner. The damper damps the motion of the toner agitator when the toner agitator rotates freely. The position indicator is attached to the toner agitator and transmits a signal indicative of a rotational position of the toner agitator. An external detector is provided on the image-forming unit and detects the signal when the toner agitator is rotated.
The damper is disposed in a path through which the toner agitator rotates, the damper damping the motion of the toner agitator when the toner agitator is within a range of rotational angle.
The damper is formed of a resilient film material bent into a base portion fixed to an inner surface of the toner cartridge and a raised portion extending into the path.
The damper is one of two dampers. A first one of the two dampers is disposed at an upstream end of the range of rotational angle with respect to rotation of the toner agitator. A second one of the two dampers is disposed at a downstream end of the range of rotational angle with respect to rotation of the toner agitator.
The raised portion of the first one of the two dampers has a plurality of slits formed in a direction in which the raised portion of the first one of the two dampers extends.
The second one of the two dampers is disposed such that the raised portion lies in a plane at an angle with the axis.
The toner agitator is rotatable freely about the axis. The second portion operates such that when the toner agitator rotates freely within the range of rotational angle, the second portion repels the toner agitator to stay within the range of rotational angle. The second portion operates such that when the toner agitator is rotated by the drive member, the second portion allows the toner agitator to move out of the range of rotational angle.
The toner agitator is pushed by a drive member to rotate about a substantially horizontal axis. When the toner agitator is rotated past its vertical highest position, the toner agitator drops from the vertical highest position due to its own weight and rotates about the substantially horizontal axis. When the toner agitator is substantially in the range of rotational angle, the signal is detected.
The position indicator is a magnet attached to the toner agitator and radiates a magnetic field. The detector is a magnetoresistive element and detects the magnetic field.
The toner agitator stays within the range of rotational angle for a shorter time when the toner cartridge holds a larger amount of toner therein than when the toner cartridge is nearly empty of toner.
An image-forming unit receives a toner cartridge attached thereto. The toner cartridge includes a toner agitator free to rotate and a position indicator that indicates a rotational position of the toner agitator. The toner agitator is driven in rotation when it is pushed to rotate. The image-forming unit includes a space that receives the toner cartridge therein and a detector that detects the position indicator when the position is at a certain rotational position.
The position indicator is a magnet that radiates a magnetic field and the detector is a magnetoresistive element that detects the magnetic field.
The toner agitator is pushed by a drive member to rotate about a substantially horizontal axis. When the toner agitator is rotated past its vertical highest position, the toner agitator drops from the vertical highest position due to its own weight. When the toner agitator is substantially in the range of rotational angle, the detector detects the magnetic field.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.